红外光谱法与焦磷酸消化法测定粉尘中游离二氧化硅含量的比较

目的比较红外光谱法与焦磷酸消化法测定粉尘中游离二氧化硅的可行性。方法对粉尘中游离二氧化硅含量用上述2种方法分别进行测定,比较2种方法测定结果。结果红外光谱法与焦磷酸消化法测定游离二氧化硅含量值差异无统计学意义（P〉0.05）,游离二氧化硅含量在0～100.03 mg范围内与吸光度值有良好的线性关系,相关系数r=0.9996。样品加标回收率为93.08%～95.01%,测定结果的相对标准偏差不大于5.21%（n=5）。结论红外光谱法可以实现高精度快速批量检测,可以逐步取代焦磷酸消化法。     

焦磷酸法测定粉尘中游离二氧化硅含量的实验条件研究

以《工作场所空气中粉尘测定第4部分:游离二氧化硅含量》(GBZ/T192.4—2007)焦磷酸法为基础对三种不同游离SiO2含量的粉尘(用1、2、3号表示)进行测定,溶解时间为10 min、15 min、20 min,过滤过程采用四种不同来源的慢速定量滤纸进行比对,灰化过程分别采用两种型号马弗炉(用Ⅰ、Ⅱ号表示),灰化时间为30 min、45 min、60min。不同溶解时间测定1号粉尘的游离SiO2含量差异无统计学意义(P0.05),不同溶解时间测定的2、3号粉尘的游离SiO2含量差异有统计学意义(P0.05),其中溶解时间10min测定的游离SiO2结果明显高于溶解时间≥15 min的测定结果 (均P0.05)。采用四种来源的慢速定量滤纸过滤测定1、2、3号粉尘的游离SiO2含量差异均无统计学意义(均P0.05)。Ⅰ号马弗炉30 min的灰化时间测定三种粉尘游离SiO2含量结果均高于标准参考值(P0.05),Ⅱ号马弗炉不同灰化时间(30 min、45 min、60 min)测定三种粉尘的游离SiO2含量结果差异均无统计学意义(P0.05)。焦磷酸法测定粉尘中游离SiO2含量时,溶解时间应不低于标准要求的15min,实验过程中应加强对滤纸过滤效果和马弗炉灰化温度的质控,必要时应适当延长灰化时间。     

实验室粉尘质控样品的制备

目的 建立实验室粉尘质量控制样品(质控样品)的制备方法.方法 使用球磨机、粉尘筛、干燥箱及混合容器等仪器设备制备粉尘质控样品,用焦磷酸法测定粉尘游离二氧化硅含量,并对粉尘质控样品进行均匀性检验.结果 本次使用的铁矿石粉尘游离二氧化硅含量为2.57%,粉煤灰粉尘游离二氧化硅含量为8.21%,石英粉尘的游离二氧化硅含量为97.36%.将石英粉尘分别与粉煤灰粉尘、铁矿石粉尘按一定比例混合,制备的两种粉尘质控样品游离二氧化硅含量分别为10.52%和4.58%,经均匀性检验,每种样品内10个样品之间的游离二氧化硅含量差异无统计学意义(P＞0.05),符合均匀性的要求.结论 该方法适用于实验室粉尘质控样品的制备.     

红外分光光度法与焦磷酸重量法测定粉尘中游离二氧化硅的比较

本文对矿山粉尘和铸造粉尘的游离二氧化硅含量进行了红外分光光度法和焦磷酸重量法的对比测定。结果表明,红外法与重量法的结果之间有很好的相关性,其测定值在统计学上无显著性差异。两法测定值的相关回归方程:(?)=1.0001×-2.0610,r=0.947997。红外法的测定不受灰化的影响,对滤膜采集的粉尘中游离二氧化硅的含量测定是一简便、快速的方法,可较好地排除粉尘中难溶或不溶物质和无定形二氧化硅等因素的干扰,克服了重量法的不足。     

粉尘中游离二氧化硅测定过程探讨

目的 通过对焦磷酸法测定粉尘中游离二氧化硅中试剂、温控和过滤等因素的改进,优化焦磷酸法测定粉尘中游离二氧化硅的过程,保证结果的准确性。方法 粉尘样品加入20 ml焦磷酸在245℃～250℃消化20 min,加热蒸馏水(50℃～80℃)稀释至150 ml～200 ml。取慢性定量滤纸(Whatman grade 42)过滤后再用0. 1 mol/L HCl洗涤。最后用热蒸馏水洗到中性为止。恒重后用重量法计算结果。结果 粉尘样品的结果在≤10%和10%～50%时,焦磷酸体积和消化时间的增加对样品的结果差异无统计学意义(P 0. 05)。而当样品≥50%时,焦磷酸体积和消化时间的增加对样品的结果差异有统计学意义(P 0. 05)。滤纸A和B的透率分别为7. 96%和6. 76%,滤纸C的透率为0. 83%。结论 优化后的焦磷酸重量法,避免了样品稀释过程中胶体的产生,解决了消化试剂用量和消化时间不足导致的结果偏高。选用更优质的滤纸减少了样品粒度过细时透滤带来的误差,优化后的测定方法准确性更高。     

焦磷酸重量法测定粉尘游离二氧化硅的有关问题商榷

粉尘中游离二氧化硅含量的测定有焦磷酸重量法、红外分光法、Ｘ线衍射法、激光喇曼光谱法、原子吸收分光光度法和钼兰比色法等方法[1] ,其中焦磷酸重量法是国家标准局推荐的唯一方法。该方法虽然能够被广泛应用 ,但是 ,操作复杂 ,费时 ,过程长 ,容易造成误差。在这里对操作中的一些问题进行讨论。1　引起过滤慢的因素1 1　操作过程中的温度因素　焦磷酸加热超过 2 5 0℃后易形成胶状沉淀物影响过滤速度。用 85 %磷酸制作焦磷酸时 ,一定要控制温度在 2 5 0℃以内 ,有些操作者在制作焦磷酸时 ,一直加热到磷酸不冒泡为止 ,此时焦磷酸的温度已超…     

煤矿粉尘中游离二氧化硅4种测定方法的比较

目的比较4种不同方法检测煤矿粉尘游离二氧化硅含量的差异。方法通过焦磷酸法(A)、焦磷酸-氢氟酸法(B)、焦磷酸-红外分光光度法(C)、红外分光光度法(D)测定煤矿粉尘游离二氧化硅含量,并比较检测结果之间的差异性。结果 4种方法检测结果两两比较(A Vs B、A Vs C、A Vs D、B Vs C、B Vs D、C Vs D)t检验结果(P值)分别为0.995、0.959、0.949、0.954、0.944、0.990。4种方法检测结果之间不存在显著差异性。结论红外分光光度法在平顶山地区煤炭行业测定粉尘中游离二氧化硅时,代替焦磷酸法是可行的;该法能够满足煤矿职业病防治过程中批量检测和监测粉尘游离二氧化硅的要求;该法与焦磷酸法检测其他行业粉尘游离二氧化硅含量结果的差异性还有待进一步研究。     

焦磷酸法测定粉尘中游离二氧化硅方法的改进

参照GBZ/T 192.4-2007焦磷酸法测定粉尘中游离二氧化硅，改进操作步骤，测定质控和实际样品，并对实验结果分析评估。结果显示，25 ml锥形瓶更适合溶解样品，焦磷酸冷却到80℃左右转移至80～100℃的蒸馏水中，可避免白色浑浊的产生；10～20 ml的焦磷酸用量对检测结果无明显影响；200 ml的焦磷酸稀释液过滤时间最短，样品中游离二氧化硅的含量越高过滤时间越长。改进后的方法准确可靠，更为简单、安全、高效，满足实验室的检测需求。     

金属硅对焦磷酸法测定呼吸性粉尘中游离二氧化硅含量的干扰研究

目的 探讨焦磷酸法测定金属硅作业场所呼吸性粉尘中游离二氧化硅含量时可能存在的干扰因素对测量结果的影响。方法 主要从焦磷酸对金属硅呼尘的溶解作用、氢氟酸对实验结果的影响、滤膜对游离二氧化硅呼尘检测结果的影响3个环节验证焦磷酸法测定金属硅作业场所呼吸性粉尘中游离二氧化硅含量的可行性。结果 3个环节的实验结果偏离已知指标较大,金属硅的回收率为66.8%;金属硅经氢氟酸处理后的平均回收率为142.5%;游离二氧化硅呼尘的最大回收率仅为43.2%。结论 焦磷酸法测定金属硅作业环境中呼吸性粉尘中游离二氧化硅含量时,检测结果的误差较大。实验结果为进一步研究改进作业场所游离二氧化硅分析检测方法的必要性提供了依据。     

磷酸法测定粉尘中游离二氧化硅方法探讨

目的探讨磷酸法测定粉尘中游离二氧化硅的方法。方法现场采样按GBZ 159.2004执行,将GBZ/T 192.4-2007中的焦磷酸法改良为磷酸法进行检测。结果用磷酸法和国标法分别进行6平行样品分析,方差分析两法检测结果差异无显著性。结论用磷酸法测定工作场所中不含焦磷酸难溶物质的粉尘中游离二氧化硅,可行性强,操作易于掌握,检测结果准确度高。     

The preparation and characterization of fine dusts carried out in the Clinica del Lavoro di Milano in support of experimental studies

This paper aims to illustrate the conditions selected at the Clinica del Lavoro of the University of Milan to prepare and analyze a large number of fine dust samples produced over a period of about 50 years, that were initially used for studies within the Clinic performed in its own facilities, and since 1956 were sent to other Italian and overseas laboratories (Luxembourg, UK, Germany, Norway, Sweden, South Korea, USA). The total quantity of material distributed (with maximum size 7-10 microns) was about 2 kg and consisted of the following mineral and artificial compounds: quartz, HF-treated quartz, tridymite, HF-treated tridymite, cristobalite, chromite, anthracite, quartz sand for foundry moulds, sand from the Lybian desert, vitreous silica, pumice, cement, as well small quantities of metallic oxides, organic resins, chrysotile, crocidolite, fibres (vitreous, cotton and polyamidic). About half of the entire quantity of dusts produced consisted of partially HF-treated tridymite. Initially, research on the etiology of silicosis used quartz dust samples, simply sieved or ventilated (consisting of classes finer than 0.04 mm, containing a 15-20% respirable fraction). From 1956 to 1960 the dusts were produced by manual grinding in an agate mortar, below about 10 microns, starting from quartz from Quincinetto (near Ivrea, Province of Turin), containing about 99.5% quartz: particle size and composition were checked using an optical-petrographic technique, with identification of the free and total silica content. Subsequently, the dusts used for biological research were obtained by grinding coarse material with a cast iron pestle and planetary mills, agate and corundum jars. The grinding products were sized by means of centrifugal classification, using the selector developed by N. Zurlo, ensuring control of dust size both optically and by means of wet levigators and hydraulic classifiers (in cooperation with the Institute of Mines of Turin Polytechnic School). After 1990 pestles and rotating drum mills with autogenic grinding load were used for grinding: the size of the treated samples was reduced to 0.05 mm and an extremely fine fraction was extracted, smaller than 7-10 microns, which was used for pneumoconioses research. The characterization of the dust produced was in any case achieved by means of preliminary examination under the optical microscope (polarized light, sometimes supplemented with phase contrast), followed by quantitative analysis using chemical/petrographic, chemical diffraction or, more commonly, petrographic/diffraction techniques. Microscopic examination, if necessary supplemented with photo-micrography, was also used for particle size control, for numerical counting and subsequent reference to weight proportion. For all operational procedures the essential data on instruments and methods are reported. During studies on production, separation of fine dusts and their characterization, partly performed with support from the European Community (EEC/European Coal and Steel Commission), the following topics in particular were addressed: connections between particle size and free silica content in the measurable dust size fraction of the grinding products and in airborne dusts; characteristics of the dusts and risk indices in Italian iron and pyrite mines; possibility of abatement of the ultrafine classes of airborne dusts in pneumatically filled stopes by the addition of salts; comparison of the latest dust selectors used within the European Community; influence of the grinding methods on the results of fibrous and soft mineral measurement using X-ray diffraction analysis.     

工作场所粉尘中游离二氧化硅含量焦磷酸测定法的影响因素

目的准确测定工作场所粉尘中游离二氧化硅含量,为评价粉尘危害提供可靠依据。方法用改进后的焦磷酸法对普通玻璃、硬质玻璃、石英玻璃、硅胶、硅藻土、焦磷酸难溶矿物,包括黄玉、刚玉、锆英石、绿柱石、电气石、碳化硅以及方石英和鳞石英进行实验分析,研究其在焦磷酸和氢氟酸中的溶解对游离二氧化硅定量测定的影响,以及石英在焦磷酸中的损失对游离二氧化硅定量测定的影响。结果粉尘中含有普通玻璃、硅胶、黄玉、刚玉、锆英石时,不影响粉尘中游离二氧化硅含量的测定,而硬质玻璃、石英玻璃、硅藻土、绿柱石、电气石、碳化硅的存在则影响游离二氧化硅的测定结果,方石英和磷石英在焦磷酸中的溶解损失影响耐火材料和陶瓷生产等工业粉尘中游离二氧化硅含量的测定,石英溶解损失也对游离二氧化硅测定存在影响。结论明确某些物质对工作场所粉尘中游离二氧化硅含量测定的影响,从而对游离二氧化硅在工作场所粉尘中的存在状况做出正确判断。     

不同消化方法及条件对牛奶中钙 锌含量测定的影响分析

目的 :探讨不同消化方法及条件对牛奶中钙、锌含量测定的影响 ,确定最佳测定条件。方法 :分别对牛奶样品进行干式灰化及湿式消化 ,用原子吸收分光光度法测定其钙、锌含量。结果 :测牛奶中钙含量选用干式灰化法和湿式消化法处理样品对测定结果无显著影响 (P >0 0 5 ) ,两种方法的回收率、精密度均符合实验要求 ;测牛奶中锌含量选用湿式消化法测得的回收率 (96 1% )明显高于干式灰化法 (88 3% )。结论 :测牛奶中钙含量选用干式灰化法和湿式消化法均可 ,干式灰化法宜选用 5 5 0℃ 4h消化 ,稀释液选择含La3 + 2 %的盐酸溶液 (1%HCl) ;测锌选用湿式消化法较好 ,以 1%HCl溶液做稀释液 ;湿式消化法的消化液宜选用 5∶1HNO3-HClO4混合酸。     

Historical respirable quartz exposures of industrial sand workers: 1946-1996

BACKGROUND: Besides a clear relationship to silicosis, crystalline silica-quartz-has been associated with lung cancer, nonmalignant renal disease, and auto-immune disease. To study diseases associated with crystalline silica further, NIOSH conducted a cohort mortality study of workers from 18 silica sand plants, which had quarry, crushing, and bagging operations to produce industrial sand. Twelve of these plants also had grinding mills to produce fine silica powder. The historical crystalline silica exposures of workers at these plants were estimated to facilitate exposure-response analyses in the epidemiologic study. METHODS: NIOSH obtained personal respirable dust measurement records from Mine Safety and Health Administration (MSHA) compliance inspections at all 18 plants and from the archives of seven plants which had collected samples. These samples had been analyzed for quartz content by x-ray diffraction. Although no personal samples were available before 1974, impinger dust measurements were reported for 19 silica sand plants in 1946; these data were converted and used to estimate exposures prior to 1974. Statistical modeling of the samples was used to estimate quartz exposure concentrations for workers in plant-job-year categories from the 1930s when mortality follow-up of the cohort began until 1988 when follow-up stopped. RESULTS: Between 1974 and 1996, there were 4,269 respirable dust samples collected at these 18 plants. The geometric mean quartz concentration was 25.9 microg/m(3) (GSD = 10.9) with a range from less than 1 to 11,700 microg/m(3). Samples below 1 microg/m(3) were given a value of 0.5 microg/m(3). Over one-third of the samples -37%) exceeded the MSHA permissible exposure limit value for quartz (PEL = 10 mg/m(3)/(%quartz + 2)) and half (51%) of the samples exceeded the NIOSH recommended exposure limit (REL=50 microg/m(3)). The samples were collected from workers performing 143 jobs within the 18 plants, but too few samples were collected from many of the jobs to make accurate estimates. Therefore, samples were combined into 10 categories of jobs performing similar tasks or located within the same plant area. CONCLUSIONS: The quartz concentrations varied significantly by plant, job, and year. Quartz concentrations decreased over time, with measurements collected in the 1970s significantly greater than those collected later. The modeled exposure estimates improve upon duration of employment as an estimate of cumulative exposure and reduce exposure misclassification due to variation in quartz levels between plants, jobs, and over time. Am. J. Ind. Med. 38:389-398, 2000. Published 2000 Wiley-Liss, Inc.     

Determination of free silica in dust particles: effect of particle size for the X-ray diffraction and phosphoric acid methods

The X-ray diffraction method and the phosphoric acid method are widely used to determine the fraction of free silica (mainly quartz and other silica polymorphs) in respirable dust sampled in working environments in Japan. In this study, we clarified the size effect of quartz dust for the X-ray diffraction method and the phosphoric acid method using size controlled quartz samples. The quartz samples were classified into 6 fractions with different size ranges: 1 microm and smaller, 1 to 3 microm, 3 to 5 microm, 5 to 7 microm, 7 to 10 microm and 10 microm and larger. Both of the determination methods were affected by the particle size, and especially particles smaller than 3 microm fairly dissolved in hot phosphoric acid and reduced X-ray diffraction intensity remarkably. If the content of these fine particles in the standard quartz sample is lower than that of the test samples, the fraction of free silica may be underestimated by these methods. For this reason, the standard quartz sample should have a representative size distribution of the field samples. The dust samples containing quartz were collected at a foundry and dissolved by phosphoric acid to remove non-quartz materials. The size fractions of dissolved samples were 50% for 5-10 microm, 25% for 3-5 microm, 20% for 1-3 microm and 5% for 1 microm and smaller. As the size distribution is similar to the present standard sample widely used in Japan, we concluded that the standard sample is suitable for these determination methods.     

石墨炉原子吸收光谱法测定尿中镉

目的:探索简便快速准确检测尿中镉的方法。方法:采用Triton X-100稀释首次350℃通氧灰化,再次450℃灰化、原子化温度1500℃,0.1%硝酸钯+0.06%硝酸镁作为基体改进剂,石墨炉原子吸收法测定。结果:增加通氧灰化能有效消除积炭干扰,线性范围为0μg/L～5μg/L,回收率为97.7%～104%,检测限为0.24μg/L,精密度测定相对标准偏差为2.7%～5.9%。结论:本方法标准曲线配置简便、样品测定快速准确灵敏,能满足大批量尿样的检测工作。     

响应面法优化石墨炉原子吸收光谱法直接测定小鼠全血铅

[目的]探讨响应面法优化石墨炉原子吸收光谱法直接测定全血中铅。[方法]以0．5％Triton X-100溶液做血液稀释剂,0．05％氧化钯＋0．1％硝酸混合溶液为基体改进剂,直接进样测定。在单因素的基础上,采用中心组合设计和响应面分析法优化灰化温度、原子化温度和基体改进剂用量等因素,并在优化条件下测定小鼠全血铅结果。[结果]响应面法优化石墨炉原子吸收谱法直接测定小鼠全血铅的最优测定条件为灰化温度760．85％,原子化温度2486．80％,基体改进剂加入量0．97mL。在已优化的条件下测定铅的检出限为0．204μg／L,相对标准差（n=6）为1．76％。染毒小鼠的全血铅含量为82．1μg/L,加标回收率为96．5％-98．4％。[结论]响应面法优化石墨炉原子吸收光谱法不需消化和离心,直接进样,简便快速和准确,适用于染毒小鼠全血铅的测定。     

全血中铅的石墨炉原子吸收测定方法

目的研究基体改进剂和升温程序对石墨炉原子吸收光谱法测定血铅的影响,找出能稳定、灵敏、准确地测定血铅的基体改进剂和升温程序。方法比较不同的基体改进剂及含量与吸光度的关系,确定最佳的基体改进剂组合;测绘温度-吸光度曲线来确定升温程序。结果基体改进剂采用0.10%硝酸钯+0.06%硝酸镁混合使用;升温程序采用灰化温度500℃30 s、原子化温度1800℃3 s。血浓度0~600μg/L范围内标准曲线线性良好,r=0.999 0,样品RSD%为1.43%~3.66%,方法的检出限:4.21μg/L。结论本方法样品无需消化处理直接进样,方便快捷且灵敏度、准确度满足工作要求,适合大批量样品的检测工作。     

某石英砂有限公司粉尘危害调查报告

目的通过对某石英砂有限公司的尘肺病危害调查,了解接尘工人的健康状况,以采取有效的防控措施。方法采用现场职业卫生调查、职业卫生检测、职业健康监护等方法 ,对工作场所中矽尘、游离二氧化硅等进行监测以及对接尘工人尘肺体检结果进行综合分析。结果工作场所矽尘检测8个岗位,有6个岗位不符合职业接触限值PC-TWA要求,游离二氧化硅检测4个样品,含量为43.1%～44.3%;噪声强度有7个岗位不符合职业接触限值要求;52名工人进行尘肺体检,诊断尘肺病9例。结论该石英砂有限公司生产车间矽尘浓度高,空气中的游离二氧化硅浓度在40%以上,噪声强度大,说明该石英砂有限公司尘肺危害严重,须对生产工艺、防护措施进行整改,切实保护工人的身体健康。